Corrosion metal loss is one of many causes of structural damage. Various means can be used to detect and monitor corrosion in structures so that, when detected, appropriate maintenance and remedial measures may be taken to protect the structure from further corrosion damage and prolong the service life of the structure. When the metallic parts of a structure are readily accessible for testing, corrosion can be detected by using nondestructive detection methods such as visual inspection, ultrasonic thickness measurements, etc.
However, when the metallic parts of the structure are not readily accessible, such as in the case of rebar in concrete structures, suspension bridge main cables, or buried pipelines, measurements of actual corrosion damage are difficult to obtain. In these situations, corrosion damage may be inferred from indirect means that sense or measure parameters related to corrosion, such as temperature, moisture, chloride ions, strain, and/or electrochemical potential or current. Yet, these means do not provide information regarding corrosion metal loss.
To minimize corrosion related damage, detection of corrosion in its initial stages of development is needed so that corrective measures could be taken early. Accordingly, a need exists for methods that detect relatively small corrosion metal losses in the structural component, for example loss on the order of microns.